Specific Protein Attachment to Artificial Membranes via Coordination to Lipid-Bound Copper(II)

D. R. Shnek, D. W. Pack, D. Y. Sasaki, F. H. Arnold

Research output: Contribution to journalArticlepeer-review

119 Scopus citations


A versatile and convenient method for targeting proteins to lipid assemblies using metal ion coordination is described. Mixed lipid bilayers and Langmuir monolayers containing a metal-chelating lipid and divalent copper ions are shown to bind protein via surface-accessible histidine residues. Cu2+ chelated by iminodiacetate (IDA) in the headgroup serves as an affinity ligand to target the protein to the interface. The compact, uncharged Cu2+‒IDA headgroup can be incorporated into lipid assemblies without disrupting the lipid packing. Surface pressure‒area isotherms of DSPC monolayers containing 5 mol % of IDA‒lipid show that Cu2+ enhances the rate and extent of myoglobin association with the interface. Myoglobin binds to small unilamellar vesicles containing 2% Cu2+‒IDA lipid (48% DSPC and 50% cholesterol) at least an order of magnitude more tightly than to vesicles without metal or loaded with Ca2+. The Cu2+‒IDA lipid more than doubles the amount of protein targeted to the interface. Cu2+ ESR parameters g and A, measured for liposomes with native and DEPC-modified myoglobin, support coordination of surface histidine side chains to Cu2+ as the binding interaction.

Original languageEnglish
Pages (from-to)2382-2388
Number of pages7
Issue number7
StatePublished - Jul 1 1994

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Spectroscopy
  • Electrochemistry


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